[xwiki-users] too many open files with Lucene

Hello, Since the migration from 4.1.3 to 4.4, there are "too many open files" alerts in Tomcat (release 5.5). I changed limit from 1024 (default value) to 4096 but the problem is not solved. It seems there are many open files used by lucene : Total tomcat open files :

/usr/sbin/lsof |grep java | wc -l 3318

Lucene open files :

/usr/sbin/lsof |grep java | grep "/xem/data" | wc -l 2524

Lucene "deleted" open files :

/usr/sbin/lsof |grep java | grep "/xem/data" | grep deleted | wc -l 1663

This behavior is new with 4.4. There is a known problem with Lucene ? Thank you Ncg